This Shared Instrumentation Grant proposal is for a single, state-of-the- art ultrasonography system to be used primarily for mouse echocardiographic studies. Advances in ultrasound now allow real-time, high resolution imaging of the mouse heart, providing noninvasive measurements of ventricular wall thickness, chamber dimensions, systolic function and Doppler measurements. Noninvasive cardiac measurements allow serial assessment of cardiac function in the same animal; this greatly reduces the numbers of animals required to establish phenotypes and increases the ability of detecting temporal changes. The Principal Investigator is an NIH-funded, trained echocardiographer and molecular biologist with the technical experience to supervise use of this device, and who will assure that this device and necessary expertise will be available to all users in this proposal. Through the use of an ultrasound device for research studies (currently on loan, to be returned in January 2001), we have gained valuable expertise in mouse echocardiography over the past two years. Our capability of performing mouse echocardiography has led to numerous publications and has already contributed substantially to NIH-funded projects in our institution. This award is critical for the continuation of our projects, as it will provide the essential equipment for noninvasive studies. If this award is not funded, alternative means such as sacrificing large numbers of animals or delaying studies by sending animals to other institutions may be necessary for many projects.